Pelvis 06: Urinary System and GI Tract Flashcards
How do the ureters move urine?
Peristalsis
Detrusor muscle
The muscle that lines the wall of the bladder; is controlled by visceral motor nerves
What are the defining points of the uretal trigone?
The openings of the ureters and the internal urethral orifice
Internal urethral orifice
The opening of the urethra from the bladder
What is the renal blood flow?
Renal artery -> segmental artery -> interlobar artery -> arcuate artery -> interlobular artery -> afferent and efferent arterioles of the superficial glomeruly -> afferent and efferent arterioles of the juxtamedullary glomeruli -> vasa recta
About how many nephrons are in a kidney?
2 million
What does a nephron consist of?
Renal corpuscle, proximal convoluted tubule, Loop of Henle, Distal convoluted tubule, collecting tubule
What is the path of urine after the nephron up to the minor calyx?
Collecting duct -> Ducts of Bellini -> Area cribosa -> minor calyx
Area cribosa
The apex of the renal papila, where urine drains to the minor calyx
Renal corpuscle
Consists of the glomerulus and Bowman’s capsule
Medullary rays
Medulla-like tissue found in the renal cortex to house superficial glomeruli
Glomerulus
The capillary bed surrounded by Bowman’s capsule in the renal corpuscle
Podocytes
Cells at the vascular pole of Bowman’s space that cover the capilaries
What is the epithelium that covers the vascular and urinary poles of the parietal layer Bowman’s capsule?
Simple squamous epithelium
Mesangium
A group of mesangial cells that are basement membrane-like and are continuous with the basement membrane between capillaries and podocytes; they are secretory cells
How is blood filtered in the renal corpuscle?
Fenestrations in the endothelium allow particles to seep through. They are filtered through the capillary basement membrane and filtration slits between podocyte cells before entering into Bowman’s space
What is the main histological difference between the proximal and distal convoluted tubules?
Proximal: brush border
Distal: no brish border
What is the epithelium of the collecting duct?
Simple columnar with rounded apices
Juxtaglomerular apparatus
An apparatus at the apposition of the distal convoluted tubule and the afferent arteriole of the glomerulus
Macula densa
A group of cells at the distal convoluted tubule found at the juxtaglomerular apparatus; densly packed and columnar
Lacis cells
Specialized cells found between the afferent arteriole and the distal convoluted tubule of the juxtaglomerular apparatus
What does the Renin-angiotensin-aldosterone system do?
It regulates (increases) blood pressure
What are the three mechanisms of the renin-angiotensin-aldosterone system?
1) sympathetic stimulation increases renin secretion by arteriole cells
2) baroreceptors of the juxtaglomerular apparatus have decreases stretch yields
3) Macula densa senses decrease in sodium concentration
Uroletrium
Translational epithelium found from minor calyx to proximal urethra; umbrella cells that can contract and distend
Median umbilical ligament
A ligament that is connected to the umbilical artery and the apex of the bladder
What is the superior surface of the bladder related to?
Peritoneum
What is the posterior surface of the bladder related to?
In males: rectum
In females: vagina
Pubovesical ligament
A ligament that runs from the pubis and around the urethra underneath the bladder in females
Puboprostatic ligament
A ligament that runs from the pubis and around the prostate in males
In males, what is the bladder related to laterally?
Paravesical pouches
In males, what is the bladder related to superiorally
Small intestines (1 point) and peritoneum (3 points)
In males, what is the bladder related to inferiorly?
Prostate
In males, what is the bladder related to anteriorly?
Retropubic space
In males, what is the bladder related to posteriorly?
Retrovesicle pouch, ureters, deferent duct, seminal vesicles, rectum
Denonvillier fascia
A fascia that separates the rectum and bladder in males
Where do sympathetics of the bladder go to?
Detrusor muscle and internal urethral sphincter
Where do parasympathetics of the bladder go to?
Detrusor muscle and internal urethral sphincter
What do visceral sensory afferents of the bladder sense?
Sensation of bladder fullness
What do visceral non-sensory afferents of the bladder sense?
Distention of the bladder
What are the sources of the inferior hypogastric plexus?
Superior hypogastric plexus; ventral rami of S2,3,4; sympathetic trunk
Pelvic splanchnics
Nerves that take out visceral afferents (nonsensory and bottom half of sensory) from the bladder and bring in parasympathetics
Hypogastric nerves
Nerves that take out visceral sensory afferents from the top half of the bladder
What do visceral sympathetic nerves do to the bladder?
Inhibit the detrusor muscle and activate the internal urethral sphincter
What do visceral parasympathetic nerves do to the blader?
Activate the detrusor muscle and inhibit the internal urethral sphincter
What are the sphincters of the male urethra?
Internal and external urethral sphincters
What innervates the external urethral sphincter(s)?
S2-4 via the pudendal nerve
What are the sphincters of the female urethra?
External urethral sphincter, urethrovaginalis, compressor urethrae (all external)
Some clinicians believe there is no internal sphincter
What happens neurologically when the bladder fills at low volumes?
Visceral non-sensory afferents are stimulated; they excite Onuf’s nucleus to maintain tone of external sphincter and excite T12-L1 to inhibit detrusor muscle
What happens neurologically when the bladder fills at high volumes?
Visceral sensory afferents signal to L1-2; PMC inhibits sympathetics to the bladder, excites parasympathetic, and inhibits Onuf’s nucleus
Pontine micturition center
PMC; a nervous site that controls bladder full response
Neurogenic bladders
A condition that results when there is bladder dysfunction at the neurological level
Reflexive neruogenic bladders
Bladder reflexes are intact; can be inhibited or uninhibited
Inhibited reflexive neurogenic bladder
Connection between pons and sacrum is broken; prevents sphincters from relaxing
Uninhibited reflexive neurogenic bladder
PMC cannot be controlled by the frontal lobe; urinary incontinence like a small infant
Nonreflexive neurogenic bladder
Bladder reflex is broken in the spine; bladder overflows
Rectal ampulla
The section of the rectum where the feces are stored
Anal canal
A canal that starts at the pelvic diaphragm and runs to the anus
Transverse rectal folds
Three folds found in the rectum
Anal columns
Column-like folds found in the anal canal
Anal sinuses
Valve-like sinuses found at the bottom of the anal columns
Pectinate line
The line that is formed by anal sinuses where aprocrine glands are found
Anal crypts
Blind sacs at the bottom of anal sinuses and are covered by anal valves
What innervates the internal anal sphincter?
Sympathetics of the hypogastric plexus and parasympathetics of S2-S4
What innervates the external anal sphincter?
Pudendal nerve of S2-S4
Puborectalis muscle
A muscle of the pelvic diaphragm that is innervated by S4 and is relaxed during defacation
Recto-anal transition zone
Where the rectum becomes the anal canal; it is NOT the same as the pectinate line
